Conventional packages of the foregoing kind have been made hitherto by forming, according to the vacuum process, cups from a thermoplastic, synthetic sheet web material, heated sufficiently to be shaped by deep-drawing, placing into said cups the filling material and subsequently covering them by a supplied cover sheet. Thereafter, the packages together with the cover sheet are cut in different ways, for instance by knives guided in longitudinal and transverse direction thereto. While such means are priced reasonably, the resultant packages have sharp corners which do not only affect the outer aspect, but also may cause injuries in use. After all, due to said sharp edges, packages not being stacked above one another may damage adjacent packages during transport. In case of many packages consisting of composite sheets, i.e. of a number of sheet layers, the package content may lose its value by a damage of the external layer, because very frequently, articles are wrapped which, unless food is at stake, are kept in the package for many years.
According to a second known method, the cover face is trimmed by a punch knife to obtain the desired three-dimensional shapes and correspondingly round corners. However, such punch knives are very expensive and, from time to time, they have to be refinished or replaced to ensure a clean cut. Punch knives are also adapted to trim circular covers. Thus, use may be made also of containers made of injection-molded plastics. The stated devices are applicable but only in case of larger quantities of uniform packages. If size or spatial shape of the packages vary, resetting operations, in particular concerning the punch knives, are required with the proviso that the total punching unit has to be disassembled to be replaced by another. For the mentioned reasons and, above all, due to the costs involved therewith, many small factories or other enterprises processing small quantities per unit of time or having a large assortment of different kinds of packages may only realize a reasonably priced packaging by a high outlay. As a result thereof, such factores have recourse, for economic deliberations, to the above mentioned unfavorable solution of cutting with a longitudinal and a transverse knife.
It is an object of the invention to facilitate as much as possible packaging by cups of thermoplastic sheet material closed by a cover sheet thus enabling small factories to perform such operation at a reasonable price in case of low quantities and of varying spatial shapes of the packages.